The present invention relates generally to image displaying method and apparatus, and especially to image displaying method and apparatus that can display an image of the inside of an object such as a blood vessel, an intestine, a stomach and a bone.
There are a variety of medical images such as an X-ray Computerized Tomography (CT) image, a Magnetic Resonance Imaging (MRI) image, an ultrasonic tomographic image and so on obtained by an X-ray CT apparatus, an MRI apparatus (including MRI for three-dimensional measurement), an ultrasonic diagnosing apparatus, a cone-beam CT apparatus for three-dimensional measurement. An image reconstructed from data obtained by a three-dimensional measurement is called a volume image. A method in which a viewpoint and a projection plane are set and an original image (multiple tomographic images) between the viewpoint and the projection plane is projected as if the original image were seen from the viewpoint has been proposed as a method of acquiring a three-dimensional method from the image obtained by an apparatus. The central projection method and the parallel projection method are known as projection methods.
To obtain an image (endoscope-like image) as if the inside of an object were seen with an endoscope, the central projection image in which the viewpoint can be set in the object is used. The central projection method for obtaining the endoscope-like image is described in detail in Japanese Patent Provisional Publication Nos. 7-210704 and 8-16813. The viewpoint and the line of sight in the central method are sequentially updated so that an endoscope-like projected image is obtained. The viewpoint and the line of sight are sequentially updated in such a way that an operator manually operates an inputting device such as a mouse, or they are sequentially and automatically updated so that the line of sight is directed toward the farthest position from the viewpoint.
However, in case of an endoscope-like image in the central projection image, for example, an image of the inner wall of a blood vessel, it is difficult to realize which blood vessel of the object is displayed and from which position of the blood vessel and in which direction the blood vessel is observed.
The present invention has been developed in view of the above-described circumstances, and has its object the provision of an image displaying method and apparatus in which a sectional image of an object such as a blood vessel and an intestine that is longitudinally cut along a curved surface along the object and an image of the object cut-open so that the inside of the object can be observed including macro information on the vicinity of viewpoints can be displayed.
To achieve the above-mentioned object, the present invention is directed to an image displaying apparatus, comprising: a viewpoint setting device that sets a plurality of viewpoints in an object included in a three-dimensional original image; a section setting device that sets, as a section, a curved surface including the plurality of viewpoints set by the viewpoint setting device; an image constructing device that constructs a sectional image of the three-dimensional original image including a sectional image of the object by cutting the three-dimensional original image along the section set by the section setting device; and a displaying device that displays the sectional image constructed by the image constructing device.
According to the present invention, viewpoints used in the central projecting method are recorded and they can be used as the viewpoints set by the viewpoint setting device. The section setting device sets the curved surface including the set viewpoints, and the image constructing device constructs the sectional image of the original image cut along the set section. Thus, the sectional image is a longitudinal sectional image of the object such as a blood vessel cut along the curved surface along the object.
In the present invention, the three-dimensional original image including the object is projected onto the predetermined projection plane and the projected image is shaded to construct the three-dimensional image and the three-dimensional image in which the viewpoints set by the viewpoint setting device are superimposed on the three-dimensional image is constructed. The longitudinal sectional image and the three-dimensional image may be displayed on one screen and may be switched.
Two curved surfaces may be used as sections when straight lines composing the curved surfaces are perpendicular to each other, and two sectional images of the object cut along the curved surfaces can be displayed. Curved surfaces as the sections may have different angles. For example, curved surfaces that have angles changing by the same angle within the range of 0xc2x0-360xc2x0 are set as the sections, and sectional images of the original image cut along the sections are sequentially displayed. Thus, the inside of the object such as a blood vessel can be observed as an animation at angles within the range of 0xc2x0-360xc2x0.
The original image including the sectional image is projected on a predetermined projection image instead of the sectional image and the projected image is shaded to construct a three-dimensional image, and the three-dimensional image is displayed.
The image displaying apparatus according to the present invention has an area designating device that designates an area for resetting at least some of the plurality of viewpoints and a resetting device that resets the viewpoints in the area designated by the area designating device according to viewpoints outside the area by interpolation, and the section setting device sets a curved surface including the plurality of viewpoints set by the viewpoint setting device and the viewpoints reset by the resetting device as a section. The viewpoints set by the viewpoint setting device are displaced from the center of the blood vessel if a thrombus is in the blood vessel. The viewpoints in the area (area designated by the area designating device) is reset from the viewpoints out side the area by interpolation.
To achieve the above-mentioned object, the present invention is directed to an image displaying apparatus, comprising: a viewpoint setting device that sets a plurality of viewpoints in an object included in a three-dimensional original image; a light source setting device that sets, as an imaginary line light source, a curved line intersecting the plurality of viewpoints set by the viewpoint setting device; an image constructing device that projects, with shading, the three-dimensional original image including the object onto a tube-shaped projection surface with the imaginary line light source set by the light source setting device being center and develops the tube-shaped projection surface with the shading to construct a three-dimensional image; and a displaying device that displays the three-dimensional image constructed by the image constructing device.
The light source setting device sets the curved line intersecting the viewpoints, and the image constructing device projects the three-dimensional original image onto the tube-shaped projection surface with the line light source being center from the set line light source and shades the projected image and develops the tube-shaped projection surface to construct the three-dimensional image. Thus, the three-dimensional image is of a cut-open object such as a blood vessel.
In the present invention, a viewpoint setting device sets a plurality of viewpoints in a branching object and a section setting device sets a curved surface including the plurality of viewpoints set by the viewpoint setting device as a section. An image constructing device constructs a sectional image of the three-dimensional original image cut along the set section. Thus, the sectional image is of the branching object.
In the present invention, the original image is cut along a curved surface and a sectional image is displayed as a plane. When two points of the object is designated on the sectional image displayed by a displaying device, a distance calculating device calculates the distance between the two points.
In the present invention, when a designating device designates a region inside the object, an area calculating device calculates the area of the region designated by the designating device.